1. Field of the Invention
The present invention relates to a generator having diverse power-generation characteristics, comprising a rotor of permanent magnets mounted on a rotator shaft supported in a stator frame for rotation, and a stator arranged around the rotor.
2. Description of the Prior Art
Modern advanced permanent magnets of high performance have become much employed on a rotor of a generator/motor. Moreover, as the generator/motor having the rotor structure of permanent magnets is high in efficiency of electromechanical energy conversion and simple in construction, its use has recently grown in industrial machines and instruments of various kinds. Then, much research and development have continued to make the generator/motor compact or slim in construction, with even high performance and high power output, and correspondingly necessitated a diversity of parts and components.
In order to increase a torque at low speed in the conventional generator/motors, it is effective to increase the strength of the magnetic field of the stator around the rotor, thereby raising the torque. With the generator/motors, thus, increasing well the torque causes the increase of electromotive force at a low speed, contributing to the provision of commercially viable power source for machines. Among the rotating machinery employing the permanent-magnet rotor is, for example a permanent-magnet rotating machine disclosed in Japanese Patent Laid-Open No. 272850/1987. The prior permanent-magnet rotating machine has a rotor in which permanent magnets are arranged and containers are provided to contain therein magnetic material that is allowed to flow radially owing to the revolution of the rotor to thereby form magnetic pole pieces.
Moreover, another prior art of an a-c generator/motor developing a high-power output is disclosed in Japanese Patent Laid-Open No. 236260/1995, in which a magnetic flux density is controlled in proportion to the rpm of the rotor to adjust properly an amount of the generated amperes or voltages. A control ring is arranged between the rotor and the stator for rotation relatively of them and further a permeable member is provided in such a manner as to come in and out contact with the control ring.
In the meantime, as most automotive electric equipments are designed to require either 12V or 24V, the automotive alternators need to have the generation characteristic capable of feeding the electric power matching to the voltage recited just above. Nevertheless, the d-c power of either 12V or 24V is too low to operate the machinery and instruments mounted on an automobile, in which much power is required for their operation. The low tension is apt to be much subject to transmission loss in the associated wiring. Moreover, a major problem exists in which too thick in cross section of conductor is necessitated for the winding. To cope with this, the alternator is needed producing not only the electric power of low voltage matching to the voltage required for the automotive electric equipments but also another electric power having high tension of about 100V or 200V and so on, which is enough to reduce the transmission loss in the wiring and render the conductor such as winding thin in cross section, thereby making it possible to drive the auxiliaries constructed compact or slim.
With the permanent-magnet generator/motor, the permanent magnet is fixed in magnetic flux density. Thus, the increase of the torque at a low speed needs to either make the permanent magnet large in size or increase the current and also increase the number of loops or turns in the winding to intensify the strength of the magnetic field at the stator side. To realize much torque, it is necessary to make the conductor wound on the stator core heavy in cross section and also the number of turns large to carry much current, thereby increasing the magnetic force of the stator. Nevertheless, too heavy in cross section of the winding conductor laid in a slot of the stator core makes it tough to lead the conductor through the slot between any adjacent teeth in the stator core and embed the windings in the slot of the stator core. In addition, since most the stator core are constructed in such a configuration that the slots are open radially inwardly while the outer periphery is closed with a cylindrical magnetic path, it is much hard to lead the windings through the slot from the inside hollow space in the stator core and wind them on the associated teeth, for the sake of which there has been some tendency to reduce the occupancy of the conductors in the associated slot.
In order to cope with the major consideration stated just earlier on the fabrication of the stator of the generator/motor, there has been conventionally proposed a production method in which teeth of the toothed member for the stator are first laid in juxtaposition and then the winding turns are wound in the slot. Thereafter, the toothed members are assembled into the complete cylindrical configuration. However, yet another problem with the production method recited earlier is to require additional fabricating operation: separating the stator core into many teeth or notching the stator core each tooth.
In the normal electric rotating machines, the windings to produce sinusoidal waveforms are wound spanning some teeth of the stator with either a concentrated-winding or a distributed-winding technique. Nevertheless, the production method recited earlier in which the toothed members are laid side by side is unsuitable for the distributed-wound field winding rather than the concentrated-field winding because the winding loops are not allowed to overlap with each other at the junctions between the adjacent toothed members.
It is a primary object of the present invention to overcome the problems stated earlier and to provide a generator having diverse power-generation characteristics, in which more than one windings either distributed-wound or concentrated-wound in slots between any adjacent teeth are connected in parallel and/or in series, with changed in combination to ensure powers different in voltage from one another, each of which may be applied across any loads requiring different voltages, for example automotive electric equipments of 12Vxcx9c24V and auxiliaries such as heaters, largemotors and so on of 100Vxcx9c200V. Moreover, an object of the present invention is to provide a generator having diverse power-generation characteristics, in which a stator core is formed in a cylindrical configuration with teeth being arranged around the outer periphery of the stator core in a manner extending radially outwardly to provide slots opened radially outwardly, while windings are laid in the slots with either concentrated-winding or distributed-winding to mount the winding on the radially outwardly extended teeth, and a cylindrical magnetic path fits over the radially outwardly extended teeth, on which the windings have been wound, thereby making it possible to manufacture the stator with ease.
The present invention is concerned with a generator with diverse power-generation characteristics, comprising a rotor shaft supported for rotation in a stator frame, a rotor mounted against rotation on the rotor shaft, and a stator arranged around the rotor and fixed to the stator frame, wherein the stator is comprised of an inside cylinder arranged around the rotor to define an air gap between confronting surfaces of them, teeth arranged spaced circumferentially on the inside cylinder to form sequential slots, an outside cylinder surrounding around tooth tips of the teeth, more than one systems of stator windings either concentrated-wound or distributed-wound with a preselected slot span, one of which is low power windings each containing a small number of turns while another of which is high power windings each containing a large number of turns, and terminal lines having terminals connected to any preselected low power and high power windings.
In an aspect of the present invention, a generator is disclosed, wherein the stator has a stator core including a circular toothed member and a cylindrical magnetic path, the circular toothed member being composed of the inside cylinder and the teeth that are integral with the inside cylinder and extend radially outwardly to form the slots opened radially outwardly, and the cylindrical magnetic path being prepared separately from the toothed member and fit over the toothed member.
In accordance with the generator constructed as stated earlier, the stator core with the radially outwardly opened slots contributes to the increase of occupancy of conductors in the slots and also makes it easy to prepare the windings to produce more than one voltages as well as facilitates the change of the voltages, or the change of the desired number of turns in the winding.
In another aspect of the present invention, there is disclosed a generator in which the cylindrical magnetic path is closely press-fit over sequential tooth tips of the teeth of the toothed member, together with a cylinder of soft material superior in magnetic permeability. Moreover, a resinous material is poured on the stator then, followed by solidified to hold in place the stator windings laid in the slots between any two adjacent teeth of the toothed member.
In another aspect of the present invention, a generator is disclosed, wherein the stator windings are led through radially outward slot openings of the slots between the adjacent teeth of the toothed member and wound spanning some slots, while the cylindrical magnetic path fits over the toothed member in which the windings laid in the slots have been held in place with the resinous material.
In another aspect of the present invention, a generator is disclosed, wherein the stator windings concentrated-wound or distributed-wound around a field pole corresponding to any pole of the rotor are shunt from series connections into parallel connections as an rpm of the rotor increases, thus regulating a generated voltage.
In another aspect of the present invention, a generator is disclosed, wherein an electric power produced in the low power windings is supplied to an automotive electric system while an electric power produced in the high power windings is fed to auxiliaries.
In another aspect of the present invention, a generator is disclosed, wherein the produced power is regulated by on-off operations of switches installed in lines connecting the stator windings with the terminals.
In a further another aspect of the present invention, a generator is disclosed, wherein the rotor comprises a permanent-magnet member composed of permanent-magnet pieces arranged spaced from each other around the rotor shaft and resinous adhesives bonding together any adjacent permanent-magnet pieces, and a reinforcing member of non-magnetic property surrounding around the permanent-magnet member, the reinforcing member being coated at the inside surface thereof with adhesives. In addition, a permeable member may be disposed between the rotor shaft and the permanent-magnet member.
More particularly, the present invention relates to a generator with diverse power-generation characteristics, comprising a rotor supported for rotation in a stator frame and having mounted with permanent magnets of multiple poles, and a stator arranged around the rotor and fixed to the stator frame, wherein the stator is composed of a stator core having teeth arranged spaced circumferentially to form sequential slots and confronting an outer periphery of the rotor to define an air gap between them, and more than one windings wound spanning across the slots, the windings being each grouped into three winding sets that are divided circumferentially with a slot span on the stator core, the windings belonging to each winding set being wound displaced in slot circumferentially 120 electrical degrees apart to form a three-phase system of windings, and wherein terminals are distributed uniformly over an inside circumference of the stator such that the windings in a 2nd winding set are arranged in the stator slots so as to overlap with a 1st winding set in waveform of emf, while a 3rd winding set overlaps with the 1st set and the 2nd set in waveform of emf, and a controller unit changes over connections of the terminals every winding sets, thus giving any electric power varied in voltage.
In an aspect of the present invention there is disclosed a generator in which the winding are grouped into any of three and four winding sets, which are laid in the slots displaced circumferentially of the inside cylinder.
In another aspect of the present invention there is disclosed a generator in which an a-c power produced in the windings in the winding sets is rectified at a rectifier circuit, and the resultant rectified power is adjusted by a chopper circuit to a preselected voltage.
In another aspect of the present invention there is disclosed a generator in which the winding sets are each constructed in mutually independent electric power source where the produced power may be used either remained a-c form or converted to d-c form.
In another aspect of the present invention there is disclosed a generator in which terminals of the windings in the winding sets are selectively connected in series and/or parallel by the controller unit, whereby a low tension induced in the windings of the winding sets is consumed in automotive electric systems, whereas a high tension is consumed to energize the heaters incorporated in diesel particulate filters and so on equipped on automotive vehicles and/or to drive the auxiliaries mounted on the vehicles.
In another aspect of the present invention there is disclosed a generator in which the windings for high tension are divided into three winding sets and distributed-wound, the terminals of the windings are selectively connected in series and/or in parallel by the controller unit, and the windings for low tension are concentrated-wound to produce the low tension that is needed to operate the automotive electric system of 24V and so on.
In a further aspect of the present invention there is disclosed a generator in which the controller unit connects all the concentrated-wound winding sets in series to ensure the maximum high tension, connects any of the concentrated-wound windings in series to ensure any tension less than the maximum high tension and further connects all the concentrated-wound windings in parallel to produce the minimum tension.
In another aspect of the present invention there is disclosed a generator in which the controller unit controls an inverter to convert direct to alternating form to drive a motor by the electric power produced in the windings in the winding sets.
In another aspect of the present invention there is disclosed a generator in which the winding sets are such arranged that working windings come in symmetry on generation.
In another aspect of the present invention there is disclosed a generator in which the windings in the winding sets are connected to form either a wye-connection or a delta-connection to provide a three-phase system of windings, and ends of the wye-connected or delta-connected windings are connected in series to the terminals through a relay.
Most automotive electric systems need the power of about 0.5 KWxcx9c1 KW at the voltages of 12Vxcx9c28V, whereas the auxiliaries mounted on the automobile need the power of about 2 KWxcx9c3 KW. If someone could get the voltages of 12Vxcx9c28V to cover the power of about 2 KWxcx9c3 KW for the auxiliaries, the current value would become too large, thus causing power loss with much heating. As opposed to the condition stated earlier, the auxiliaries or auxiliary machinery is allowed to operate on the high tension of about 100Vxcx9c200V, thus involved in no problem of power loss in the wiring. Accordingly, the winding adapted to produce the high tension supplied to the auxiliaries, for example is allowed to make slender or thin the conductor in cross section, thereby contributing to rendering the generator slim in construction and light in weight. Besides, when any relay is used, the voltage may be more increased with the result of less current, thus protecting any contact against possible fusion.
With the generator according to the present invention, simply connecting in series and/or in parallel the terminals of the windings in the winding sets is sufficient to produce any of high, medium and low tensions. That is to say, the controller unit connects all the three winding sets in series to ensure the maximum high tension, and connects any two of the windings in series or connects all the windings in parallel as the desired tension reduces to any tension below the maximum high tension. The high tension given by the series connections of the windings in the winding sets is consumed, for example to energize the heaters incorporated in diesel particulate filters and so on equipped on automotive vehicles and/or to drive the auxiliaries mounted on the vehicles. The low tension produced by the parallel connections of windings in the winding sets is uses for the automotive electric systems.
With the stator employed in the generator of the present invention, the stator windings, as being allowed to be led through radially outward slot openings of the slots between the adjacent teeth of the toothed member, may be distributed-wound or concentrated-wound on the stator core with ease, thus helping ensure the stator rich in reliability. Especially, the windings in the winding sets distributed-wound or concentrated-wound on the stator core are distributed circumferentially in slot every phase and every pole in a manner the magnetic figures are displaced stepwise and the winding curves verge on the sinusoidal form. This makes it possible to make the windings in the slots with efficiency and ease.
With the generator constructed according to the present invention, any one power developed in the low-power windings serves as the power necessary for energizing the automotive electric systems while another power produced in the high-power winding is used for the actuation of the auxiliaries such as the heater of the diesel particulate filter, air-conditioner and the power-take-off or the like. The winding connections for high power to generate the high tension may reduce the current value, which is needed of gaining the desired power, thus rendering the conductor small in cross section. This makes it possible to provide the generator compact or slim in overall construction, with even lower transmission loss in the wiring.
Power (W) of the generator, in general, is expressed as W=Sxc3x97Nxc3x97"PHgr", where S is rpm of the rotor, N is the number of turns and "PHgr" is the magnetic flux density. With the equation stated just above, since both the rpm(S) of the rotor and the flux density ("PHgr") are assumed constant, the increase of the power (W) will be realized only as the number (N) of the turns increases.
Most prior generators make it tough in construction to wind the conductor on the stator core. To cope with the tough problem on winding operation, the stator core in the generator of the present invention is constructed in such a manner that the slots between any adjacent teeth are open radially outwardly of the stator. This construction of the stator core makes it easy to distributed-wind or concentrated-wind two types of the windings on the stator core, which differ in the number of turns, to thereby provide the generator having the diverse power-generation characteristics.
Effective emf (E1) per one pole is given by the equation: E1=(2)xcfx80f "PHgr"m where f is the frequency and "PHgr"m is the effective magnetic flux per a pole.
The effective emf (E1m) in light of the number of turns is expressed as E1m=(2)xcfx80f "PHgr"mxc2x7kw N1 where kw is the winding factor and N1 is the overall number of the windings. That is, the efficiency is somewhat dependent on the winding factor.
In the generator having the multi-pole permanent-magnet rotor, for example, the first windings to produce the power for the vehicle are divided into a winding group less in the number of turns and another winding group more in the number of turns. Each winding group is composed of windings wound, each spanning a slot per one pole, and other windings wound, each spanning across an empty slot and an opposite slot, all the windings being wound sequentially in series. In the stator where the windings are made on the stator core as explained above, it will be reasoned based on the above E1m that the small power is produced by the windings small in the number of turns while the large power is developed by the windings large in the number of turns.
With the generator having the stator core on which the windings are wound in a manner as stated earlier, all the windings less in the number of turns are connected in series when the rpm of the rotor is small. The produced power is converted through to a pulsating current, which is in turn rectified through coils and condensers. As the rpm of the rotor increases, the power is taken out from a half or a third of the all windings the, followed by rectification. As an alternative, the system may be employed, in which the negative sides of the a-c are cut. Thus, when the vehicle loads are regulated with the battery voltage in matching with the tension regulation stated just above, the d-c steady in voltage ranging over the whole operating range may be ensured. On the other hand, the windings having a large absolute number of turns have the ability to produce power of 100V at even low rpm. When the rpm of the rotor goes too high, the voltage may be regulated as in the windings less in the number of turns. Moreover, the three-phase a-c to drive the induction motor may be provided by any inverter.
In the generator of the present invention, the windings are allowed to be wound on the stator core by laying the conductor in the slots through the outward slot openings from the outside of the toothed member rather than by leading the conductor through the slots inside the stator core as in the conventional stator production. Thus, the winding operation may be performed with much ease. The windings laid in the slots are then held in place with resinous material and the cylindrical magnetic path is press-fit over the radially outward tooth tips of the toothed member. Thus, the stator may be completed with ease. According to the present invention, the windings, prior to the pres-fit of the cylindrical magnetic path over the toothed member, are concentrated-wound or distributed-wound on the stator core by laying the conductor in the slots through the outward slot openings from the outside of the toothed member. This construction improves the production efficiency of the stator and succeeds in providing the reliable stators. The windings distributed-wound or concentrated-wound on the stator core are distributed circumferentially in slot every phase and every pole in a manner the magnetic figures are displaced stepwise and the winding curves verge on the sinusoidal form. This makes it possible to lay the windings in the slots with efficiency and ease.
With the generator according to the present invention, any one power developed in the low-power windings serves as the power necessary for energizing the automotive electric systems while another power produced in the high-power winding is used for the actuation of the auxiliaries such as the heater of the diesel particulate filter, air-conditioner and the power-take-off or the like. The winding connections for high power to generate the high tension may reduce the current value, which is needed of gaining the desired power, thus rendering the conductor small in cross section. This makes it possible to provide the generator compact or slim in overall construction, with even lower transmission loss in the wiring.
Other objects and features of the present invention will be more apparent to those skilled in the art on consideration of the accompanying drawings and following specification wherein are disclosed preferred embodiments of the present invention with understanding that such variations, modifications and elimination of parts may be made therein as fall within the scope of the appended claims without departing from the spirit of the invention.